In manufacturing semiconductor devices, fine processing with lithography using photoresists has been conventionally performed. The fine processing includes: forming a thin film of a photoresist on a semiconductor substrate such as a silicon wafer; irradiating the substrate with active light such as ultraviolet through a mask pattern having a pattern of semiconductor device; developing the substrate; and treating the substrate by etching with an obtained photoresist pattern as a protection film. In such a manner, fine concavities and convexities matching the pattern are formed on the surface of the substrate. In recent years, semiconductor devices have become highly integrated, and a wavelength of active light to be used has become shorter, such that from KrF excimer lasers (248 nm) to ArF excimer lasers (193 nm) and EUV light (13.5 nm).
Thus, controlling of profiles (resist shapes) and improved adhesion to substrates are required for resists more than before.
As an underlayer film between a semiconductor substrate and a photoresist, a hardmask that is a film containing a metal element such as silicon has been used. In this case, the components of a resist and a hardmask significantly differ from each other, and thus the removal rates of them by dry etching largely depend on gas species used in dry etching. By selecting proper gas species, a hardmask can be removed by dry etching without larger decrease in the film thickness of a photoresist. As stated, in recent years, a resist underlayer film has been placed between a semiconductor substrate and a photoresist in manufacturing of semiconductor devices so that a variety of effects are achieved (see Patent Documents 1 and 2).
Although investigations have been made to compositions for resist underlayer films so far, development of novel materials for resist underlayer films are required for satisfying various requirements for properties of the resist underlayer films.